The Centers for Disease Control and Prevention recently reported two U.S. cases of antifungal-resistant Trichophyton indotineae, a mold species that has been primarily active in South Asia in recent years. Commonly referred to as “ringworm,” the fungus is highly transmissible and can cause tinea, an infection of nails, hair and skin that can be severe. According to the CDC, the two U.S. cases are especially concerning because the affected patients share no epidemiological connections and their infections have not been responsive to oral terbinafine treatment.
The issue is additionally challenging because the infection is frequently misdiagnosed as T. mentographytes or T. interdigitale. In fact, T. indotineae is sometimes referred to as T. mentographytes type VIII. For this reason, they explain genomic sequencing is required to confirm the correct diagnosis.
Unfortunately, the dermatophyte (a type of fungus reliant on keratin) often expresses mutations that have equipped it with antifungal resistance. Until now, cases in Europe and the U.S. have been rare, but treatment-resistant ringworm has reached epidemic levels in India. Antimicrobial resistance (AMR) resulting from the overuse and misuse of treatment medications has been a growing public health concern. In fact, the World Health Organization has listed it as one of the top 10 global public health threats. To help combat AMR, the CDC emphasizes that proper use of antifungal drugs and corticosteroids is essential.
What you need to know:
- Tinea is common and highly contagious.
- State and local health departments can provide assistance with testing for health care providers who suspect T. indotineae infections.
- Treatment options include oral itraconazole, a triazole antifungal, but CDC advises there are multiple considerations including absorption issues, drug interactions, potential of therapy for up to 12 weeks, and the documented emergence of triazole resistance.
What you can do:
- Stop the spread of dermatophytes by educating patients on prevention practices. www.cdc.gov/fungal/diseases/ringworm/risk-prevention.html
- Support testing and surveillance efforts to help monitor and track the spread of T. indotineae.
- Public health officials who are concerned about potential cases of drug-resistant tinea infections can email fungaloutbreaks@cdc.gov for assistance with recommendations and testing.
References:
www.cdc.gov/fungal/diseases/ringworm/dermatophyte-resistance.html
www.cdc.gov/mmwr/volumes/72/wr/mm7219a4.htm
www.cdc.gov/fungal/diseases/ringworm/risk-prevention.html
www.who.int/news/item/15-05-2023-new-who-report-highlights-progress-but-also-remaining-gaps-in-ensuring-a-robust-pipeline-of-antibiotic-treatments-to-combat-antimicrobial-resistance-(amr)
Nicole Cloutier is a Research Associate for the SPECTRE Program.